The map is represented by surfels, where each surfel is defined by a position \(\mathbf {v}_s \in \mathbb {R}^3\) , a normal \(\mathbf {n}_s \in \mathbb {R}^3\) , and a radius \(r_s \in \mathbb {R}\) .
Each surfel additionally carries two timestamps: the creation timestamp \(t_c\)  and the timestamp \(t_u\)  of its last update by a measurement. Furthermore, a stability log odds ratio \(l_s\)  is maintained using a binary Bayes Filter [1]} to determine if a surfel is considered stable or unstable.
SuMa also performs loop closure detection with subsequent pose-graph optimization to obtain globally consistent maps.
